State the principles of production of EM waves. An EM wave of wavelength `lamda` goes from vacuum to a medium of refractive index n. What will be the frequency of wave in the medium?

Explanation

An accelerated charge produces oscillating electric field in space, which produces an oscillating magnetic field, which in turn, is a source of oscillating electric field and so on. The oscillating electric & magnetic fields produces each other & give rise to e.m. waves.